fix(cli): drive single-target runs with ManagedClient

Replace the manual single-target ClientSession loops in the stream and TUI adapters with ManagedClient::start_with_subscription so the existing worker owns opening, deadline-aware pacing, receive handling, timeout polling, draining, and close.

Use bounded subscription waits for interruption and input polling, drain queued events before and after join, and report per-subscription drops without changing output, statistics, labels, summaries, warning, or peer-close policy. Add process and unit regressions for 10 ms cadence, interruption, final-event draining, TUI terminal state, and overflow visibility.

crates/irtt-client/src/error.rs

@@ -169,9 +169,9 @@ pub enum EventSubscriptionError {
     /// The subscription can no longer receive new events.
     ///
     /// Already queued events are delivered first. After the queue is drained,
-    /// `recv` and `try_recv` return this error when the hub disconnects the
-    /// subscriber, the hub is shut down, or the subscription is disconnected by
-    /// its overflow policy.
+    /// `recv`, `recv_timeout`, and `try_recv` return this error when the hub
+    /// disconnects the subscriber, the hub is shut down, or the subscription is
+    /// disconnected by its overflow policy.
     #[error("event subscription is disconnected")]
     Disconnected,
 }